EP4727670A1

EP4727670A1 - Water separator for separating water from a fluid flow

Info

Publication number: EP4727670A1
Application number: EP24730249.0A
Authority: EP
Inventors: Andreas Weber; Tobias WÖRZ; Ettore Nocera; Thomas Grein; Matthias Teschner; Alexander Korn; Pius Trautmann; Thomas Schleiden; Christof Mangold
Original assignee: Mann and Hummel GmbH
Current assignee: Mann and Hummel GmbH
Priority date: 2023-06-13
Filing date: 2024-05-28
Publication date: 2026-04-22
Also published as: CN121311288A; WO2024256161A1; DE102023115366A1; KR20260021629A

Abstract

The invention concerns a water separator (100) for separating water from a fluid flow, in particular from a gas flow of a fuel cell system, comprising at least a first separation stage (10) with a first flow-conducting region (18), which is connected to a fluid conduit (17). In the fluid conduit (17), a coarse water separator (20) is arranged. A separation region (22) is connected to a water outlet (24). The water separator (100) comprises at least a second separation stage (30) with a second flow-conducting region (38), wherein the second separation stage (30) is arranged downstream of the first separation stage (10). In this context, the second flow-conducting region (38) comprises at least one separation element (50, 60) which is exposed to the oncoming fluid flow.

Description

Water Separator for Separating Water from a Fluid Flow

Technical Field

[0001] The invention concerns a water separator for separating water from a fluid flow, in particular from a gas flow of a fuel cell system.

Background Art

[0002] EP 1167743 B1 discloses a water separator which is configured as a swirl separator. The water separator comprises an inner pipe and an outer pipe which are arranged sequentially in axial direction, wherein the inner pipe projects with an axial section into the outer pipe and the outer pipe comprises a water outlet which is arranged tangentially in the swirl direction.

Summary

[0003] It is an object of the invention to provide an improved water separator for separating water from a fluid flow, in particular a gas flow of a fuel cell system.

[0004] The aforementioned object is solved according to an aspect of the invention by a water separator for separating water from a fluid flow, in particular from a gas flow of a fuel cell system, comprising at least a first separation stage with a first flow-conducting region which is connected to a fluid conduit, wherein the first flow-conducting region comprises at least one inner pipe and at least one outer pipe which are arranged in an axial direction in relation to each other, wherein the inner pipe adjoins the outer pipe and is arranged downstream of the outer pipe in flow direction, wherein in the fluid conduit a coarse water separator is arranged, wherein a separation region is arranged on a radially outer side of the inner pipe and of the outer pipe and is connected to a water outlet, comprising at least a second separation stage with a second flow-conducting region, wherein the second separation stage is arranged downstream of the first separation stage, wherein the inner pipe of the first flow-conducting region is coupled in fluid communication to an inlet opening of the second flow-conducting region, wherein the second flow-conducting region comprises at least one separation element which is exposed to the oncoming fluid flow.

[0005] Beneficial configurations and advantages of the invention result from the additional claims, the description, and the drawing.

[0006] According to an aspect of the invention, a water separator for separating water from a fluid flow, in particular from a gas flow of a fuel cell system, is proposed, comprising at least a first separation stage with a first flow-conducting region which is connected to a fluid conduit. The first flow conducting region comprises at least one inner pipe and at least one outer pipe which are arranged in an axial direction in relation to each other. The inner pipe adjoins the outer pipe and is arranged downstream of the outer pipe in flow direction. A coarse water separator is arranged in the fluid conduit. A separation region is arranged on a radially outer side of the inner pipe and of the outer pipe and is connected to a water outlet. Furthermore, the water separator comprises at least a second separation stage with a second flow-conducting region, wherein the second separation stage is arranged downstream of the first separation stage. The inner pipe of the first flow conducting region is coupled in fluid communication to an inlet opening of the second flow-conducting region. In this context, the second flow-conducting region comprises at least one separation element which is exposed to the oncoming fluid flow. [0007] The gas flow of the fuel cell system can be, for example, air, hydrogen, or nitrogen.

[0008] The proposed water separator can be used, for example, at the cathode side and/or at the anode side of a fuel cell system, at the anode side preferably in the recirculation circuit upstream of a feed pump.

[0009] Water from the reaction of hydrogen with oxygen is present as product water in a fuel cell system and is removed by means of water separators from the anode circuit. The separated water is usually discharged to the environment of the fuel cell system but, as needed, can also be reused for other components which require liquid water such as, for example, humidifiers for the process gases. Depending on the type and volume flow of the fuel cell, very high separation efficiencies of the water separator can be required which can be achieved only with a multi-stage process.

[0010] The proposed multi-stage water separator comprises advantageously a high water separation efficiency. Thus, a first separation stage serves for separation of large water quantities from the fluid flow at the air flow inlet. Here, proportions of up to 90% of the water can be separated, for example. In a second separation stage, an impactor with downstream separation components can be arranged. The latter are employed in accordance with a modular system, either all of them or some of them, in order to separate the remaining liquid water from the fluid flow. In this way, separation components for low flow rates can be advantageously combined with separation components for high flow rates, which can be arranged in a compact configuration in the housing of the second separation stage.

[0011] The water separator can be advantageously adapted to different requirements. Long service lives of the fuel cell system can thus be particularly advantageously achieved.

[0012] Advantageously, the first separation stage of the water separator can be configured as an axial cyclone. Here, by means of centrifugal forces, a wall film is generated from the liquid water of the air which drains at the inner wall of the first separation stage to the drainage.

[0013] The water droplets remaining in the air flow are guided through the inner pipe of the first separation stage configured as a connection conduit into the second separation stage in which the flow is forced to change direction multiple times. The second separation stage serves as a fine water separator for the residual water quantity of the fluid flow. In the housing of the water separator, advantageously at least one element can be provided against which the fluid flow impacts and thereby is deflected. The water droplets cannot follow the change of flow due to mass force effect and can therefore be separated. Depending on the embodiment of the housing, multiple flow deflections can take place in the second separation stage, by means of appropriately provided numerous separation elements such as, for example, a separation nonwoven, a separation impactor, a lamellar separator or the like.

[0014] Advantageously, in the proposed water separator a flow imparted with a swirl can be generated by means of an axial cyclone in the inlet region of the water separator, followed by subsequent separation of water in multiple separation stages by centrifugal force, inertia and/or gravity effects. The water separator thus differs beneficially from the prior art by an improved overall separation performance while having comparable pressure loss. [0015] The water separator can be operated advantageously in horizontal installation or vertical installation, for example, in a fuel cell system.

[0016] The water separator can be comprised of a plurality of in particular exchangeable individual parts in case of the modular system, or can be produced as a unitary component, for example, of plastic material by conventional injection molding method.

[0017] The first separation stage can be provided, for example, with a swirl generator as a coarse water separator which can be arranged either as one piece together with the fluid conduit or exchangeably arranged.

[0018] The first and the second separation stage of the water separator as well as individual elements of the second separation stage can be produced beneficially as separate components which, in case of a multi-stage water separator, can be joined modularly to an entire system in accordance with a modular system. In this context, the components and housing of the individual separation stages can be welded or glued together, for example.

[0019] According to a beneficial embodiment of the water separator, the separation element can comprise a surface structured opposite to the fluid flow direction and/or a nonwoven, wherein the structured surface comprises a plurality of elevations, in particular a plurality of parallel arranged truncated pyramids. Other forms of elevations are also possible, for example, cylinders, cuboids, spheres, cones. The fluid flow can be forced by the separation element to a change of the flow direction. Due to the sharp flow deflection of the fluid flow at the separation element and the tendency of the water droplets to move forward in a straight line, they remain in contact with the separation element for a longer period of time. The water droplets in the fluid flow remain in this context in the depth of the structured surface or in the nonwoven, become larger, and can then drain in the gravity direction downwardly into a water collection chamber.

[0020] According to a beneficial embodiment of the water separator, the separation element can be configured as an impactor plate without interior or with an interior which is downwardly open in the gravity direction. In this context, the separation element can be arranged opposite an inlet opening of the second flow-conducting region. Due to the arrangement of the separation element opposite to the inflow direction, the separation element is directly exposed to the oncoming flow and can thus force the fluid flow to a deflection of the flow direction. The impactor plate can be planar, curved, stepped or can be formed in a non-planar shape in other ways. At the separation element, which can comprise a closed surface or openings, separated water can drain through the interior and/or at the front side into the water collection chamber.

[0021] According to a beneficial embodiment of the water separator, a front side of the impactor plate exposed to the oncoming fluid flow can be configured as a structured surface. Water droplets can deposit or separate advantageously at the elements of the structured surface and drain downwardly in the gravity direction into a water collection chamber.

[0022] According to a beneficial embodiment of the water separator, at least one passage opening can be arranged in the front side of the impactor plate for passage of the fluid flow into the interior of the impactor plate. In this context, the at least one passage opening can have an arbitrary shape and size. In particular, holes of a plurality of passage openings can have an arbitrary shape and size. Holes of a plurality of passage openings can be configured in the form of a perforation of the impactor plate. In this way, at least one part of the fluid flow can pass through the front side into the interior of the impactor plate. Liquid water of the fluid flow can thus advantageously deposit at the wall of the calmed flow interior and be separated from the fluid flow in this way.

[0023] According to a beneficial embodiment of the water separator, drainage channels for outflow of the separated water in the gravity direction can be provided at the front side of the impactor plate. In this way, water separated at the separation element can flow more easily downwardly and thereafter can be discharged in a targeted fashion into the water collection chamber.

[0024] According to a beneficial embodiment of the water separator, the nonwoven can be arranged in the interior and/or at the front side of the impactor plate. The nonwoven can thus contribute to separation of water at different locations of the separation element and can at least partially absorb the separated water.

[0025] According to a beneficial embodiment of the water separator, a first calmed flow region, in particular a calmed flow region of a drainage chamber, can be formed at a side of the separation element which is facing away from the fluid flow. The calmed flow region can contribute advantageously to the additional separation of water from the fluid flow as well as guide separated wall films to the drainage point.

[0026] According to a beneficial embodiment of the water separator, the inlet opening can open into an impactor nozzle which is arranged in the interior of the second flow-conducting region and configured to guide the fluid flow against the separation element. In this manner, the separation element can be exposed to oncoming flow in a targeted fashion and the separation efficiency can be beneficially increased in this way.

[0027] According to a beneficial embodiment of the water separator, a lamellar separator can be arranged in the second separation stage. In this context, the lamellar separator can be arranged transversely to the flow direction of the fluid flow in the second flow-conducting region of the second separation stage. In particular, in this context the lamellar separator can have a cross section which corresponds to a cross section of the second flow-conducting region. The lamellar separator can be arranged such that the entire fluid flow between inlet opening and outlet opening of the second separation stage of the water separator is passed through the lamellar separator. In this way, the surface area for separation of water can be advantageously enlarged and the efficiency of the water separation can be improved in this way.

[0028] According to a beneficial configuration of the water separator, an outlet pipe of the second separation stage can be arranged in a region of the second flow conducting region which is opposite to the gravity direction. In particular, in this context the outlet pipe can be arranged in the second flowconducting region diagonally opposite the inlet opening. In this way, the fluid flow can be beneficially forced to perform a deflection of the flow direction and thus to an increased water separation within the housing. [0029] According to a beneficial embodiment of the water separator, the outlet pipe can comprise at its inlet opening a collar which is crimped away from the inlet opening. Behind the collar, the fluid flow can encounter advantageously a type of calmed flow zone which can contribute to an improved water separation.

[0030] According to a beneficial embodiment of the water separator, between the collar and a side wall of the second flow-conducting region at the outflow side a nonwoven which at least in sections surrounds the outlet pipe can be arranged. The nonwoven can contribute additionally to an improved water separation and absorption of separated liquid from the fluid flow.

[0031] According to a beneficial embodiment of the water separator, the nonwoven can be configured at least in sections as a part of a truncated cone wherein a tip of the cone is oriented in the direction toward the inlet opening of the outlet pipe. The shape together with the calmed flow zone can contribute additionally to an improved water separation and absorption of separated liquid from the fluid flow.

[0032] According to a beneficial embodiment of the water separator, a baffle plate can be arranged opposite the inlet opening of the outlet pipe transverse to the flow direction and spaced apart to a top side of the second flow-conducting region. The baffle plate can represent an additional possibility of deflection of the flow direction in the second separation stage, which can contribute to an improved water separation from the fluid flow.

[0033] According to a beneficial configuration of the water separator, an inner wall of the second flowconducting region can be arranged spaced apart in relation to a side wall at the inflow side. The additional inner wall produces a region which is separated from the fluid flow and which is shielded from the air flow in the second flow-conducting region and can therefore guide separated wall films to the drainage point.

[0034] According to a beneficial configuration of the water separator, a second calmed flow region can be formed between the inner wall and the side wall at the inflow side. By means of the second calmed flow region, it can be ensured that the already separated water droplets will not be entrained again by the fluid flow and, in this way, a further possibility for an improved water separation is advantageously provided.

[0035] According to a beneficial embodiment of the water separator, a water collection chamber can be arranged in a part of the second flow-conducting region positioned at the bottom in the gravity direction. In this context, the water collection chamber can comprise in particular a water outlet, in particular at its lowest point. Separated water can thus collect and be discharged beneficially without the already separated liquid water proportions being swirled up again and entrained by the fluid flow.

[0036] According to a beneficial embodiment of the water separator, in the water collection chamber a water siphoning device can be provided which is connected in fluid communication to the calmed flow region of the drainage chamber of the separation element. Optionally, not only can the water thus drain freely but, in particular depending on water quantity and position of the water collection chamber as well as installation position of the water separator, can be actively siphoned away additionally. Advantageously, the water siphoning device can be arranged in combination with an impactor plate which comprises an interior. [0037] According to a beneficial embodiment of the water separator, a receiving pipe with an outlet pipe arranged in the interior of the receiving pipe can be arranged at the inlet opening of the second flowconducting region. In this context, the separation element can be arranged at an inner side of the receiving pipe and can surround the outlet pipe at least partially. The outlet pipe can be closed at its downstream end at least partially and comprise a plurality of fluid passage openings positioned opposite the separation element. The fluid flow can thus be forced already by the outlet pipe to a deflection of the flow direction and can be guided to the separation element which is arranged about the outlet pipe, for example, in an annular shape. In this way, an additional separation of liquid water from the fluid flow can be effectively generated immediately after exiting from the outlet pipe.

[0038] According to a beneficial embodiment of the water separation device, the receiving pipe can be arranged in the second flow-conducting region. In a simplified embodiment, the second separation stage of the water separator can thus comprise the receiving pipe and the separation element arranged about the outlet pipe. In this way, a particularly compact configuration of the water separator is possible.

Brief Description of Drawings

[0039] Further advantages result from the following drawing description. In the drawings, embodiments of the invention are illustrated. The drawings, the description, and the claims contain numerous features in combination. A person of skill in the art will expediently consider the features also individually and combine them to expedient further combinations. It is illustrated in an exemplary fashion in schematic illustration in:

Figure 1 a section illustration of a water separator for separating water from a fluid flow, in particular from an air flow of a fuel cell system, according to an embodiment of the invention;

Figure 2 a section illustration of a water separator according to a further embodiment of the invention;

Figure 3 a section illustration of a water separator according to a further embodiment of the invention;

Figure 4 a section illustration of a water separator according to a further embodiment of the invention;

Figure 5 a section illustration of a water separator according to a further embodiment of the invention;

Figure 6 a section illustration of a water separator according to a further embodiment of the invention;

Figure 7 a section illustration of a water separator according to a further embodiment of the invention;

Figure 8 a section illustration of a water separator with a simplified second separation stage according to a further embodiment of the invention;

Figure 9 a section illustration of a water separator with a simplified second separation stage according to a further embodiment of the invention;

Figure 10 a section illustration of a water separator according to a further embodiment of the invention; Figure 11 a section illustration of a second separation stage according to a further embodiment of the invention, which is arranged downstream of a first separation stage, provided with an alternative arrangement of impactor plate and separation collar;

Figure 12 a section illustration of the second separation stage along the section line B-B according to Figure 11 ;

Figure 13 a section illustration of the second separation stage along the section line C-C according to Figure 11 ; Figure 14 a plan view of a separation element of a water separator according to an embodiment of the invention;

Figure 15 a section illustration of the separation element along the section line A-A according to Figure 14;

Figure 16 an enlarged illustration of the detail C of the section illustration according to Figure 15;

Figure 17 an enlarged illustration of the detail B of the plan view of Figure 14;

Figure 18 a plan view of a separation element according to a further embodiment of the invention;

Figure 19 a section illustration of the separation element along the section line A-A according to Figure 18;

Figure 20 a plan view of a separation element according to a further embodiment of the invention;

Figure 21 a section illustration of the separation element along the section line A-A according to Figure 20;

Figure 22 a plan view of a separation element according to a further embodiment of the invention;

Figure 23 a section illustration of the separation element along the section line A-A according to Figure 22;

Figure 24 an enlarged illustration of a detail of the section illustration according to Figure 23;

Figure 25 an enlarged illustration of a detail of the plan view of Figure 22;

Figure 26 a plan view of a separation element according to a further embodiment of the invention;

Figure 27 a section illustration of the separation element along the section line A-A according to Figure 26;

Figure 28 an enlarged illustration of the detail B of the section illustration according to Figure 27; and Figure 29 an enlarged illustration of the detail C of the plan view of Figure 26.

Description of Embodiments

[0040] In the Figures, same or same-type components are identified with same reference characters. The Figures show only examples and are not to be understood as limiting.

[0041] Figure 1 shows a schematic section illustration of a water separator 100 for separation of water from a fluid flow, in particular from a gas flow of a fuel cell system, in particular from air, hydrogen, or nitrogen, according to an embodiment of the invention.

[0042] The water separator 100 comprises a first separation stage 10 with a first flow-conducting region 18 which is connected to a fluid conduit 17.

[0043] The first separation stage 10 serves as a main separator for larger water quantities at the fluid flow inlet.

[0044] The first flow-conducting region 18 comprises an inner pipe 14 and an outer pipe 16 which are arranged relative to each other in an axial direction 82. The inner pipe 14 adjoins the outer pipe 16 and is arranged in flow direction 80 downstream of the outer pipe 16. The flow direction 80 is indicated with arrows. The first separation stage 10 is arranged here in a housing 12.

[0045] A coarse water separator 20 is arranged in the fluid conduit 17. The coarse water separator 20 can be, for example, a swirl generator in the form of an axial cyclone. In the housing 12, a separation region 22 is arranged on a radial outer side of the inner pipe 14 and of the outer pipe 16. The separation region 22 is connected to a water outlet 24 which is arranged in the gravity direction 84 at the bottom of the housing 12.

[0046] In the first separation stage 10, the air which is entering in this context via the fluid conduit 17 is guided to the coarse water separator 20. In doing so, the air is caused to rotate and exits through the funnel-shaped expanded outer pipe 16 into the separation region 22 of the housing 12. By means of centrifugal forces, the water droplets contained in the air are moved outwardly in radial direction in relation to the flow and generate a wall film at the inner wall of the water separation region 22 of the first separation stage 10 which moves in the direction toward the drainage region. The separated water can drain toward the water outlet 24.

[0047] The water separator 100 comprises furthermore a second separation stage 30 with a second flow-conducting region 38, wherein the second separation stage 30 is arranged downstream of the first separation stage 10 and combines different separation elements with each other according to a modular system. The second separation stage 30 is arranged in a housing 32.

[0048] The second separation stage 30 serves as a fine water separator for the residual water quantity in the fluid flow.

[0049] The inner pipe 14 of the first separation stage 10 is coupled in fluid communication to an inlet opening 34 of the second flow-conducting region 38. In a further embodiment, the inner pipe 14 can also project into the housing 32 for this purpose.

[0050] The second flow-conducting region 38 comprises a separation element 50 which is embodied as an impactor plate 54 which is exposed to the oncoming fluid flow entering the housing 32 of the second separation stage 30 through the inner pipe 14 and guided therein farther through the impactor nozzle 144. At the front side 56 which is oriented against the fluid flow, the impactor plate 54 comprises a structured surface 51 with pyramid-shaped elevations 57. Behind the separation element 50, at a side of the separation element 50 which is facing away from the fluid flow, a first calmed flow region 36 is formed.

[0051] A water collection chamber 76 for separated water is arranged in a part of the housing 32 which is positioned at the bottom in the gravity direction 84. The water collection chamber 76 comprises at its lowest point a water outlet 44 for draining the separated water.

[0052] The calmed flow region 36 is connected in fluid communication to the water collection chamber 76. At the side of the separation element 50 facing away from the fluid flow, a further calmed flow region of the drainage chamber 143 is formed which is connected in fluid communication to a water siphoning device 78.

[0053] The air which has impacted on the separation element 50 and has experienced thereat a deflection of the flow direction then impacts on lamellar separator 40. The lamellar separator 40 is arranged transversely to the flow direction 80 of the fluid flow in the second flow-conducting region 38. The lamellar separator 40 comprises in this context a cross section which corresponds to a cross section of the second flow-conducting region 38 so that the fluid flow in any case must pass completely through the lamellar separator 40. [0054] An outlet pipe 42 of the second separation stage 30 is arranged in a region of the second flowconducting region 38 opposite to the gravity direction 84. In this context, the outlet pipe 42 is in particular arranged diagonally opposite the inlet opening 34 of the second flow-conducting region 38 in order to achieve a beneficial flow conduction through the second flow-conducting region 38.

[0055] The outlet pipe 42 comprises at its inlet opening 46 a collar 48 which is crimped away from the inlet opening 46. Between the collar 48 and a side wall 33 of the housing 32 at the outflow side, a nonwoven 43 is arranged which surrounds the outlet pipe 42 at least in sections, in particular in an annular shape. The nonwoven 43 abuts the side wall 33 at the outflow side and is spaced apart from the top side 37 of the second flow-conducting region 38. The nonwoven 43 can have different cross sections and contour courses. In case of a corresponding material thickness, the top side 37 is at least partially contacted.

[0056] Opposite the inlet opening 46 of the outlet pipe 42, a baffle plate 70 is arranged transverse to the flow direction 80 and spaced apart from a top side 37 of the second flow-conducting region 38.

[0057] Furthermore, an inner wall 72 is spaced apart from a side wall 35 at the inflow side. Between the inner wall 72 and the side wall 35 at the inflow side, a further calmed flow region 74 is formed. The further calmed flow region 74 is also connected in fluid communication to the water collection chamber 76.

[0058] The water droplets which remain in the air flow after the preseparation of water in the first separation stage 10 are thus guided through the inner pipe 14 of the first separation stage 10, which is formed as a connecting conduit, into the second separation stage 30 in which the flow is forced to perform several directional changes.

[0059] At the location of the flow deflection, advantageously at least one element can be provided against which the fluid flow impacts and which absorbs the water droplets which cannot follow the change in flow due to the inertia effect. Depending on the embodiment of the housing 32, in the second separation stage 30 a plurality of deflections can take place with appropriately provided numerous separation elements, for example, a separation element 50 configured as impactor plate 54, lamellar separator 40, separation collar 48, separation nonwoven 43 or the like.

[0060] In the embodiment illustrated in Figure 1 , the fluid flow from the impactor nozzle 144 impacts directly on the separation element 50. At the separation element 50, the fluid flow is first slowed and deflected so that a further portion of the water entrained in the fluid flow can deposit or can be separated. The space behind the separation element 50 forms a drainage chamber 143 with a calmed flow region which is connected in fluid communication to the water collection chamber 76. As an alternative, the drainage chamber 143 with the calmed flow region can be connected in fluid communication to the water siphoning device 78.

[0061] The deflected fluid flow passes then through the lamellar separator 40. The latter serves to separate a further portion of liquid water in a region of low flow rate.

[0062] Subsequently, the fluid flow fills the upper region of the second flow-conducting region 38 in which the outlet pipe 42 with its crimped collar 48 and the nonwoven 43 arranged around it provides a further reduction of the liquid water contents. Water droplets can be separated at the baffle plate 70 which is arranged opposite the inlet opening 46 of the outlet pipe 42. The inner wall 72 with the calmed flow region 74 arranged behind it provides an additional calmed flow region 74, whereby the drainage from this part of the second flow-conducting region 38 is facilitated. The calmed flow region 74 can be beneficially connected in fluid communication to the water collection chamber 76 for this purpose.

[0063] In the embodiment illustrated in Figure 1 , the separation element 50 comprises a structured surface 51 . The structured surface 51 , which is illustrated only schematically, can comprise, for example, a plurality of elevations 57 oriented opposite to the fluid flow direction, in the illustrated embodiment parallel-arranged truncated pyramids. Due to the impact of the fluid flow on the truncated pyramids 57, the fluid flow can be slowed significantly and deflected so that liquid water can deposit on the truncated pyramids 57 and drain downwardly.

[0064] In Figure 2, a section illustration of a water separator 100 according to a further embodiment of the invention is illustrated. In this embodiment, the nonwoven 43 arranged about the outlet pipe 42 is moved away from the side wall 33 of the housing 32 and adjoins directly the crimped collar 48 of the outlet pipe 42. The nonwoven 43 can have different dimensions and shapes. The free space between side wall 33 and collar 48 can be furnished with nonwoven 43 of different size and shape. In this way, a calmed flow zone with defined properties can be additionally produced.

[0065] In this embodiment, the separation element 50 is also formed as impactor plate 54 with pyramidshaped elevations 57 of the structured surface 51.

[0066] Figure 3 shows a section illustration of a water separator 100 according to further embodiment of the invention in which the nonwoven 43 is formed in a cone shape, wherein a tip of the cone is oriented in the direction toward the inlet opening 46. With this embodiment of the nonwoven 43, an advantageous separation of liquid water from the fluid flow can be achieved also.

[0067] In Figure 4, a section illustration of a water separator 100 according to a further embodiment of the invention is illustrated in which the nonwoven 43 around the outlet pipe 42 has the same configuration as in the embodiment illustrated in Figure 3. However, the separation element 50 configured as an impactor plate 54 comprises no structured surface 51 but a nonwoven 52. Water drops which impact directly on the nonwoven 52 penetrate into the depth of the nonwoven 52 and are thereby separated from the deflected fluid flow. In the nonwoven 52, a large quantity of liquid water can thus be absorbed without being entrained again by the fluid flow. The absorbed water can then flow beneficially out of the nonwoven 52 into the water collection chamber 76.

[0068] Figure 5 shows a section illustration of a water separator 100 according to a further embodiment of the invention.

[0069] The water separator 100 is embodied substantially as in the embodiment illustrated in Figure 4. However, here a receiving pipe 62 is arranged at the inlet opening 34 of the second flow-conducting region 38, with an outlet pipe 145 received in the interior of the receiving pipe 62. In this context, a further separation element 60 is arranged at an inner side of the receiving pipe 62. The separation element 60 surrounds the outlet pipe 145 at least in sections. The outlet pipe 145 is closed at least partially at its end 28 at the downstream side. Further, the outlet pipe 145 comprises a plurality of fluid passage openings 26 positioned opposite the separation element 60. [0070] The fluid flow flowing through the inner pipe 14 can flow into the outlet pipe 145, can exit again through the fluid passage openings 26 from the outlet pipe 145, and is thus deflected in respect to the flow direction 80. In this context, the fluid flow, when it exits from the outlet pipe 145, impacts directly on the separation element 60 which is also embodied with a nonwoven 52 in this embodiment. Advantageously, a further water separation can thus take place at the additional separation element 60. The receiving pipe 62 comprises for this purpose an additional drainage 61 through which the separated water can reach the water collection chamber 76 of the housing 32.

[0071] The embodiment illustrated in Figure 5 thus represents a water separator 100 which comprises within the second separation stage 30 a further optional separation stage in the form of the separation element 60 inside the receiving pipe 62 in accordance with the modular system. In this way, a further improved separation performance can be achieved.

[0072] The section illustration of a water separator 100 illustrated in Figure 6 shows a further embodiment, similar to the embodiment illustrated in Figure 5, with a separation element 60 arranged within the receiving pipe 62 which is however provided with a structured surface 51 in contrast to the embodiment illustrated in Figure 5. The total separation performance of the water separator 100 can also be improved advantageously thereby.

[0073] Figure 7 shows a section illustration of a water separator 100 according to a further embodiment of the invention.

[0074] The important difference to the embodiments illustrated in Figures 1 through 6 resides in that the two separation stages 10, 30 are not arranged in separate housings 12, 32 which can be beneficially joined to the water separator 100 but in that the two separation stages 10, 30 are arranged in a single housing 12. In this context, the inner pipe 14 of the first separation stage 10 is formed as one piece together with the impactor nozzle 144 of the second separation stage 30.

[0075] In the embodiment illustrated in Figure 7, the separation element 50 is formed with pyramidshaped elevations 57 of the structured surface 51 . The nonwoven 43 is embodied in an arrangement as illustrated in the embodiment of Figure 1. As an alternative, the other embodiments for the separation element 50 and the nonwoven 43 illustrated in Figures 1 through 6 are possible also.

[0076] Figure 8 shows a section illustration of a water separator 100 with a simplified second separation stage 30 according to further embodiment of the invention.

[0077] This embodiment is derived from the embodiment illustrated in Figure 5. The housing 32 of the second separation stage 30 is embodied as a receiving pipe 62 at the inlet opening 34 of the second flow-conducting region 38, with an outlet pipe 145 arranged in the interior of the receiving pipe 62. In this context, a separation element 60 is arranged at an inner side of the receiving pipe 62 and surrounds the outlet pipe 145 at least in sections. The outlet pipe 145 is at least partially closed at its end 28 at the downstream side and comprises a plurality of fluid passage openings 26 positioned opposite the separation element 60.

[0078] The inner pipe 14 of the first separation stage 10 is directly coupled in fluid communication to the inlet opening 34 so that the fluid flow can flow through the inner pipe 14 into the outlet pipe 145. [0079] The fluid flow flowing through the inner pipe 14 can thus enter the outlet pipe 145, can exit again through the fluid passage openings 26 from the outlet pipe 145, and is thus deflected in respect to the flow direction 80. In this context, the fluid flow when it exits from the outlet pipe 145 impacts directly on the separation element 60 which is also formed with a nonwoven 52 in this embodiment. A further water separation can advantageously take place in this way at the additional separation element 60. For this purpose, the receiving pipe 62 comprises a water outlet 44 through which the separated water can exit from the water collection chamber 76 of the housing 32.

[0080] In this manner, a water separator 100 of a particularly compact construction can be realized which nonetheless exhibits an effective water separation capability.

[0081] The thus realized water separator 100 represents a further example of a beneficial water separator 100 built in a modular construction of individual modularly mountable components.

[0082] Figure 9 shows a further embodiment of a water separator 100 designed in this way in which according to the embodiment in Figure 6 the separation element 60 is configured as a structured surface 51 . In this way, water can also be separated effectively from the fluid flow in a very compact way.

[0083] Figure 10 shows a section illustration of a water separator 100 according to a further embodiment of the invention.

[0084] In this embodiment, the first separation stage 10 corresponds to the first separation stage 10 of the embodiments illustrated in the Figures 1 through 6. The second separation stage 30 is however of a different configuration.

[0085] The second separation stage 30 is arranged in a housing 32 and serves as a fine water separator for the residual water quantity in the fluid flow.

[0086] The inner pipe 14 of the first separation stage 10 is coupled in fluid communication to the inlet opening 34 of the second flow-conducting region 38.

[0087] The second flow-conducting region 38 comprises a separation element 50 which is formed as an impactor plate 54 which is exposed to the oncoming fluid flow which is entering the housing 32 of the second separation stage 30 through the inner pipe 14 and is further guided from there through the impactor nozzle 144. The impactor plate 54 comprises at the front side 56 facing the fluid flow a structured surface 51 , in particular with pyramid-shaped elevations 57. Behind the separation element 50, at a side of the separation element 50 which is facing away from the fluid flow, a first calmed flow region 36 is formed.

[0088] A water collection chamber 76 for the separated water is arranged in a part of the housing 32 which is at the bottom in the gravity direction 84. The water collection chamber 76 comprises at a bottom surface two water outlets 44 for draining the separated water.

[0089] The calmed flow region 36 is connected in fluid communication to the water collection chamber 76.

[0090] An outlet pipe 42 is arranged in axial direction 82 opposite the inlet opening 34 of the second flow-conducting region 38 in order to achieve a beneficial flow guiding action through the second flowconducting region 38. [0091] The outlet pipe 42 comprises at its inlet opening 46 a collar 48 crimped away from the inlet opening 46.

[0092] The water droplets which remain in the air flow after the preseparation of water in the first separation stage 10 are thus guided through the inner pipe 14 of the first separation stage 10 formed as a connection conduit into the second separation stage 30 in which the flow is forced to perform a change in direction.

[0093] At the location of the flow deflection, advantageously at least one element can be located on which the fluid flow impacts and which absorbs the water droplets which cannot follow the change in flow due to the inertia effect. Depending on the embodiment of the housing 32, a separation element 50 formed as an impactor plate 54 can be arranged in the second separation stage 30 for deflection, for example.

[0094] In the embodiment illustrated in Figure 10, the fluid flow from the impactor nozzle 144 impacts directly on the separation element 50. At the separation element 50, the fluid flow is initially slowed and deflected so that a further portion of the water entrained in the fluid flow can be deposited or separated. [0095] Subsequently, the fluid flow fills the region of the second flow-conducting region 38 in which the outlet pipe 42 with its crimped collar 48 ensures a further reduction of the liquid water contents.

[0096] The separation element 50 in the embodiment illustrated in Figure 10 comprises a structured surface 51 . The structured surface 51 which is illustrated only schematically can comprise, for example, a plurality of elevations 57 oriented opposite to the fluid flow direction, in the illustrated embodiment parallel arranged truncated pyramids. Due to the fluid flow impacting on the truncated pyramids 57, the fluid flow can be slowed significantly and deflected so that liquid water can deposit on the truncated pyramids 57 and drain downwardly.

[0097] In this context, the impactor plate 54 corresponds to the embodiment illustrated in Figure 2.

[0098] The impactor plate 54 of the separation element 50 can be inclined in relation to the axial direction 82. The impactor plate 54 can thus be arranged preferably perpendicularly to the axial direction 82, as illustrated in the embodiment. As an alternative, it is however also possible that the impactor plate is inclined in relation to the vertical at an angle 64 away from the axial direction 82 or at an angle 66 toward the axial direction 82 in order to beneficially change the separation effect of the separation element 50.

[0099] Figure 11 shows a section illustration of a second separation stage 30 according to a further embodiment of the invention, which is arranged downstream of the first separation stage 10, provided with an alternative arrangement of impactor plate 54 and separation collar 48.

[0100] The embodiment illustrated in Figure 11 can represent, for example, a realization of the second separation stage 30 of the water separator 100 illustrated in Figure 10.

[0101] The second separation stage 30 with the second flow-conducting region 38 is configured in a simplified construction in a cylindrical housing 32. Impactor nozzle 144 and separation element 50 are arranged at a defined spacing.

[0102] The separation element 50 is configured as an impactor plate 54 with pyramid-shaped elevations 51 and comprises an interior 55 which is configured as a drainage chamber 143 with a calmed flow region. In this arrangement, a further calmed flow region 36 is produced behind the separation element 50.

[0103] The outlet pipe 42 comprises a separation collar 48. A beneficially arranged water outlet 44 is connected in fluid communication to the water collection chamber 76.

[0104] In the embodiment of a second separation stage 30 illustrated in Figure 11 , impactor nozzle 144, separation element 50, separation collar 48, and outlet pipe 42 are embodied in a housing 32 in a coaxial arrangement and have defined spacings relative to each other.

[0105] The separated water collected in the water collection chamber 76 can drain via the water outlets 44.

[0106] Figure 12 shows a section illustration of the second separation stage 30 along the section line B-B according to Figure 11. A pian view of the impactor plate 54 forming the separation element 50 can be seen. The impactor plate 54 comprises a structured surface 51 with pyramid-shaped elevations 57. The impactor plate 54 can have any arbitrary shape, for example, a round or angular contour. The inner wall of the housing 12 and the outer contour of the impactor plate 54 can be spaced at a nonuniform spacing. The water outlet 44 can be seen in section.

[0107] Figure 13 shows a section illustration of the second separation stage 30 along the section line C-C according to Figure 11. In this context, a section through the outlet pipe 42 can be seen. Impactor plate 54 and separation collar 48 have a different outer contour. The housing 12 can have any arbitrary shape, for example, round or angular.

[0108] Figure 14 shows a plan view of a separation element 50 of a water separator 100 according to an embodiment of the invention. In Figure 15, a section illustration of the separation element 50 along the section line A-A according to Figure 14 is illustrated while Figure 16 shows an enlarged illustration of the detail C of the section illustration according to Figure 15 and Figure 17 an enlarged illustration of the detail B of the plan view of Figure 14.

[0109] The separation element 50 formed as an impactor plate 54 comprises a structured surface 51 , i.e. , represents an embodiment as it is used in the water separators illustrated in Figures 1 to 3. The structured surface 51 comprises parallel arranged rows of truncated pyramids 57 as elevations 57 which are oriented opposite to the fluid flow direction. The truncated pyramids 57 in immediately adjacently positioned rows are arranged offset to each other, respectively. Due to the fluid flow impacting on the truncated pyramids 57, the fluid flow can be slowed significantly and deflected so that liquid water can deposit at the truncated pyramids 57 and/or can be separated thereat.

[0110] As can be seen in particular in Figure 15, the separation element 50 is formed as an impactor plate 54 with an interior 55 which is open downwardly in the gravity direction 84. As an alternative, the separation element 50 can also have a curved shape or can be formed as a curved plate. In this context, the separation element 50 is arranged in the second separation stage 30 of the water separator 100 opposite the inflow opening 34 of the housing 32, as can be seen in Figures 1 to 3, and the fluid flow flows against directly against it. The separation element 50 can be fixed to a bottom of the housing 32, for example. [0111] In the embodiment illustrated in Figures 14 to 17 of a separation element 50, the front side 56 of the impactor plate 54 exposed to the oncoming fluid flow is embodied as a structured surface 51 .

[0112] In the detail illustrations in Figures 16 and 17, the truncated pyramids 57 of the structured surface 51 are illustrated enlarged. In this way, beneficial dimensions for the truncated pyramids 57 can be defined.

[0113] A height 110 of the truncated pyramids 57 can lie beneficially between 4 mm and 40 mm and, for example, amount to 8 mm. An edge length 111 , 112 of a base surface of the truncated pyramid 57 can lie beneficially between 1 mm and 20 mm and, for example, can amount to 4 mm. The base surface, as in the illustrated embodiments, can be advantageously square so that the two edge lengths 111 , 112 are identical. An edge length 113, 114 of an end surface of the truncated pyramid 57 can lie beneficially between 0.25 mm and 5 mm and, for example, can amount to 1 mm. When the base surface is square, the end surface beneficially can also be square so that the two edge lengths 113, 114 are identical. An angle between the lateral surfaces of the truncated pyramid 57 amounts to 21 ° for these measures, for example.

[0114] A row offset 115 between the truncated pyramids 57 of neighboring rows of truncated pyramids

57 amounts to, as can be seen in Figure 12, half an edge length 111 ofthe base surface, in the illustrated embodiment thus 2 mm.

[0115] As can be also seen in Figure 17, drainage channels 59 in the gravity direction 84 for drainage of the separated water are formed at the front side 56 of the impactor plate 54. The drainage channels 59 are positioned respectively between the rows of the truncated pyramids 57. A width of the drainage channels 59 can lie beneficially between 0.25 mm and 5 mm.

[0116] Figure 18 shows a plan view of a separation element 50 according to a further embodiment of the invention while in Figure 19 a section illustration of the separation element 50 along the section line A-A according to Figure 18 is illustrated.

[0117] In this embodiment, the impactor plate 54 comprises at its front side 56 a large passage opening

58 through which the fluid flow can enter the interior 55. The interior 55 is filled with a nonwoven 52 at which water can be separated from the fluid flow. At the bottom side of the interior 55 which is open toward the housing 32 of the second separation stage 30, the separated water can drain into the water collection chamber 76. As can be seen in Figure 19, the nonwoven can completely fill the interior 55. A depth 121 of the interior 55 as well as the thickness 120 of the nonwoven 52 can lie beneficially between 0.1 mm and 50 mm, for example, can amount to 20 mm.

[0118] In Figure 20, a plan view of the separation element 50 according to a further embodiment of the invention is illustrated while in Figure 21 a section illustration of the separation element 50 along the section line A-A according to Figure 20 is illustrated.

[0119] In this embodiment, the front side 56 of the impactor plate 54 comprises a plurality of small passage openings 58 through which the fluid flow can pass into the interior 55 of the impactor plate 54. The plurality of small passage openings 58 can be realized in the form of a perforation. Holes of the plurality of small passage openings 58 can comprise any arbitrary shape and size. As in the preceding embodiment, the interior 55 is filled with the nonwoven 52. As can be seen in Figure 21 , a further nonwoven 53 is arranged at the front side 56 of the impactor plate 54 in flow direction upstream of the passage openings 58 and can serve as a preseparation stage of water, for example.

[0120] A diameter 130 of the passage openings 58 can lie beneficially between 1 mm and 20 mm and, for example, can amount to 8 mm. A horizontal spacing 131 as well as a vertical spacing 132 between the passage openings 58 can lie between 1 .5 mm and 30 mm and, for example, can amount to 12 mm. However, the hole pattern can also be non-symmetrical so that spacings and angles of neighboring center points of the passage openings 58 can be variable. A thickness 133 of the nonwoven 52 in the interior 55 can lie between 0.1 mm and 50 mm and, for example, can amount to 20 mm. A thickness 134 of the nonwoven 53 at the front side 56 can lie between 0.1 mm and 50 mm and, for example, can amount to 4 mm.

[0121] Both nonwovens 52, 53 can be present in the separation element 50. As an alternative, it is however also possible that only one nonwoven 52 is present in the interior 55 or only one nonwoven 53 at the front side 56 of the planar impactor plate 54.

[0122] Figure 22 shows a plan view of a separation element 50 according to a further embodiment of the invention while in Figure 23 a section illustration of the separation element 50 along the section line A-A according to Figure 22 is illustrated.

[0123] In this embodiment, at the front side 56 of the impactor plate 54 a plurality of passage openings 58 are arranged wherein the regions between the passage openings are covered with the structured surface 51 with elevations 57 configured as truncated pyramids 57. The interior 55 of the impactor plate 54 is empty and forms a calmed flow zone for collection of liquid water so that the fluid flow which has entered the interior 55 can flow out again in downward direction.

[0124] Figure 24 shows an enlarged illustration of a detail of the section illustration according to Figure 23 while in Figure 25 an enlarged illustration of a detail of the plan view according to Figure 22 is illustrated. In Figures 24 and 25, arrangement and measures of the separation element 50 can be seen more clearly.

[0125] The measures and spacings of the truncated pyramids 57 correspond to the measures and spacings of the embodiment illustrated in Figures 14 to 17. The diameter 130 of the passage openings 58 can lie between 1 mm and 20 mm as in the preceding embodiment and beneficially can amount to 8 mm. A horizontal spacing 141 and a vertical spacing 142 of the passage openings 58 can lie between 3 mm and 30 mm and, for example, can amount to 16 mm.

[0126] Figure 26 shows a plan view of a separation element 50 according to a further embodiment of the invention while in Figure 27 a section illustration of the separation element 50 along the section line A-Aaccording to Figure 26 is illustrated. In Figure 28, an enlarged illustration of the detail B of the section illustration according to Figure 27 and in Figure 29 an enlarged illustration of the detail C of the plan view according to Figure 26 is illustrated, respectively.

[0127] This embodiment corresponds to the embodiment illustrated in Figures 22 to 25 with the difference that the interior 55 of the impactor plate 54 is filled up with the nonwoven 52 in the embodiment illustrated in Figures 26 to 29. [0128] In the nonwoven 52, water from the fluid flow passing through the passage openings 58 can be advantageously separated and additionally absorbed at the nonwoven 52 in this way.

[0129] The measures and spacings of truncated pyramids 57, passage openings 58, and nonwoven 52 correspond to those of the preceding embodiments.

Reference Numbers

10 first separation stage

12 housing

14 inner pipe

16 outer pipe

17 fluid conduit

18 first flow-conducting region

20 coarse water separator

22 separation region

24 water outlet

26 fluid passage opening

28 end

30 second separation stage

32 housing

33 side wall outflow side

34 inlet opening

35 side wall inflow side

36 first calmed flow region

37 top side

38 second flow-conducting region

40 lamellar separator

42 outlet pipe

43 nonwoven

44 water outlet

46 inlet opening

48 collar

50 separation element

51 structured surface

52 nonwoven

53 nonwoven

54 impactor plate

55 interior

56 front side

57 elevation, truncated pyramids

58 passage opening

59 drainage channel

60 separation element

61 drainage

62 receiving pipe 64 angle

66 angle

70 baffle plate

72 inner wall

74 second calmed flow region

76 water collection chamber

78 water siphoning device

80 flow direction

82 axial direction

84 gravity direction

100 water separator

110 height

111 edge length base surface

112 edge length base surface

113 edge length end surface

114 edge length end surface

115 row offset

116 angle between lateral surfaces

120 thickness nonwoven

121 depth interior

130 diameter passage opening

131 horizontal spacing

132 vertical spacing

133 thickness nonwoven interior

134 thickness nonwoven front side

141 horizontal spacing

142 vertical spacing

143 drainage chamber

144 impactor nozzle

145 outlet pipe

Claims

1 . A water separator (100) for separating water from a fluid flow, in particular from a gas flow of a fuel cell system, the water separator (100) comprising: a first separation stage (10) comprising a fluid conduit (17), a first flow-conducting region (18) connected to the fluid conduit (17), and a separation region (22), and a water outlet (24), wherein the first flow-conducting region (18) comprises at least one inner pipe (14) and at least one outer pipe (16) that are arranged in an axial direction (82) in relation to each other, the inner pipe (14) adjoining the outer pipe (16) and being arranged in flow direction (80) downstream of the outer pipe (16), wherein the fluid conduit (17) comprises a coarse water separator (20) arranged in the fluid conduit (17), and wherein the separation region (22) is arranged at a radially outer side of the inner pipe (14) and of the outer pipe (16) and is connected to the water outlet (24); and a second separation stage (30) comprising a second flow-conducting region (38), the second separation stage (30) being arranged downstream of the first separation stage (10), wherein the inner pipe (14) of the first flow-conducting region (18) is coupled in fluid communication to an inlet opening (34) of the second flow-conducting region (38), and wherein the second flow-conducting region (38) comprises at least one separation element (50, 60) is configured to be exposed to the oncoming fluid flow, the separation element (50) being configured as an impactor plate (54) with an interior (55) open downwardly in a gravity direction (84), the separation element (50) being arranged opposite the inlet opening (34) of the second flow-conducting region (38), and the impactor plate (54) comprising a plurality of passage openings (58) arranged in a front side (56) of the impactor plate (54) and for passage of the fluid flow into the interior (55) of the impactor plate (54).

2. The water separator according to claim 1 , wherein the separation element (50, 60) comprises a nonwoven (52, 53).

3. The water separator (100) according to claim 2, wherein the nonwoven (52, 53) is arranged in the interior (55) and at the front side (56) of the impactor plate (54).

4. The water separator (100) according to one of the preceding claims, wherein the second separation stage (30) further comprises a first calmed flow region (36) of a drainage chamber (143) of the separation element (50), the first calm flow region (36) being formed at a side of the separation element (50) facing away from the fluid flow.

5. The water separator (100) according to one of the preceding claims, wherein the second separation stage (30) further comprises an impactor nozzle (144) into which the inlet opening (34) opens, the impactor nozzle (144) being arranged in an interior of the second flow-conducting region (38) and being configured to guide the fluid flow against the separation element (50).

6. The water separator (100) according to one of the preceding claims, wherein the second separation stage (30) further comprises a lamellar separator (40) arranged transversely to the flow direction (80) of the fluid flow in the second flow-conducting region (38) of the second separation stage (30), the lamellar separator (40) comprising a cross section corresponding to a cross section of the second flowconducting region (38).

7. The water separator (100) according to one of the preceding claims, wherein the second separation stage (30) further comprises an outlet pipe (42) arranged in a region of the second flow-conducting region (38) opposite to the gravity direction (84), the outlet pipe (42) being arranged in the second flowconducting region (38) diagonally opposite the inlet opening (34).

8. The water separator (100) according to claim 7, wherein the outlet pipe (42) comprises an inlet opening (46) and a collar (48) arranged at the inlet opening (46) and crimped away from the inlet opening (46).

9. The water separator (100) according to claim 8, wherein the second flow-conducting region (38) further comprises a nonwoven (43) arranged between the collar (48) and a side wall (33) of the second flow-conducting region (38) and surrounding the outlet pipe (42) at least in sections.

10. The water separator (100) according to claim 9, wherein the nonwoven (43) is formed at least in sections as part of a truncated cone, a tip of the truncated cone being oriented in a direction toward the inlet opening (46) of the outlet pipe (42).

11 . The water separator (100) according to one of the preceding claims, wherein the second flowconducting region (38) further comprises a baffle plate (70) arranged opposite the inlet opening (46) of the outlet pipe (42) and transverse to the flow direction (80), the baffle plate (70) being arranged at a spacing to a top side (37) of the second flow-conducting region (38).

12. The water separator (100) according to one of the preceding claims, wherein the second flowconducting region (38) further comprises an inner wall (72) arranged spaced apart from a side wall (35) of the second separation stage (30).

13. The water separator (100) according to claim 12, wherein the second separation stage (30) further comprises a second calmed flow region (74) formed between the inner wall (72) and the side wall (35).

14. The water separator (100) according to one of the preceding claims, wherein the second separation stage (30) further comprises a water collection chamber (76) arranged in a part of the second flow- conducting region (38) at a bottom in the gravity direction (84), the water collection chamber (76) comprising a water outlet (44) at a lowest point of the water collection chamber (76).

15. The water separator (100) according to claim 14, wherein the second separation stage (30) further comprises a water siphoning device (78) arranged in the water collection chamber (76) and connected in fluid communication to a first calmed flow region (36) of a drainage chamber (143) of the separation element (50).

16. The water separator (100) according to one of the preceding claims, wherein the second separation stage (30) further comprises a receiving pipe (62) arranged at the inlet opening (34) of the second flowconducting region (38), and an outlet pipe (145) arranged in an interior of the receiving pipe (62), wherein the separation element (60) is arranged at an inner side of the receiving pipe (62) and at least in sections surrounds the outlet pipe (145), wherein a downstream end (28) of the outlet pipe (145) is at least partially closed, and wherein the outlet pipe (145) comprises a plurality of fluid passage openings (26) positioned opposite the separation element (60).

17. The water separator (100) according to claim 16, wherein the receiving pipe (62) is arranged in the second flow-conducting region (38).